1. Field of the Invention
The invention relates to a rotor of a gas-cooled electrical machine, especially a turbogenerator, having an excitation winding arranged in longitudinal slots on the outer circumference of the rotor body, having an excitation current supply line for connection of the excitation line, which runs centrally in the rotor in an axial shaft hole, to the excitation winding conductors in the winding overhang of the rotor, having a forced-cooled excitation supply line bolt, which is arranged in a first radial shaft hole and is electrically and mecanically connected at its inner end to the excitation line, and at its outer end, outside the rotor shaft, via connecting conductors to the conductors of the rotor winding overhang, which rotor has a rotor cap to support the winding overhang of the rotor, the rotor winding overhang space being split underneath the rotor cap by separating walls, which run essentially axially, into cold and hot gas chambers, through which cooling gas, conveyed by a fan, flows.
In this case, the invention makes reference to a prior art, as results, for example, from CH-PS 586,966.
2. Discussion of Background
In turbogenerators, the excitation lines are normally guided on the rotor to the rotor winding in a central shaft hole. The conductors in the shaft hole are generally solid and insulated all round. The connection from these centrally guided solid conductors to the rotor winding is produced via current supply line bolts which are screwed radially into the solid conductors. Such a bolt is, for example, the subject matter of the CH Patent Specification 586,966. In addition to bolts consisting of copper or of a copper alloy, bolts consisting of high-tensile steel are used in more recent designs, which must then be forced-cooled.
The bolt is located in a shaft section which is subject to extremely high stresses because of the shaft bending as a result of the intrinsic weight of the rotor and unbalanced forces. The rotor shaft is weakened by a (radial) hole in this shaft section. In the most unfavorable case, cracks can form in the region of the bolt hole, which may lead to damage.